This invention relates to disk drives that employ removable cartridges, and more specifically, to a load ramp that cooperates with an actuator to unload and load a read/write head that unlatches a removable cartridge.
Conventionally, a removable cartridge disk drive has an actuator upon which read/write heads are mounted for communicating with a disk. Actuators typically are of two types: linear or rotary. Linear actuators translate along an axis that is radial to the disk and aligned with a centerline of the actuator. Rotary actuators typically consist of a structural arm that pivots on a voice coil motor, and a suspension arm that extends from the structural arm opposite the voice coil motor. The heads are mounted to the end of the suspension arm distal from the voice coil motor.
Disk drives that employ removable disk cartridges commonly retract the actuator to disengage the heads from the disk surface before ejection of the cartridge from the drive to prevent damage to the heads and disk surface. Disk drives that employ nonremovable may also disengage the heads from the disk, especially with highly polished disks to which the heads may stick if left in motionless contact. A load ramp is typically disposed near the outer edge of the disk to facilitate loading (that is, moving the head onto the disk) and unloading (that is, moving the head off of the disk) of the heads. The load ramp may be disposed over the disk surface to lift/raise and support the suspension. Also, the load ramp may be disposed outside of the disk perimeter, in which case a lifting tab is typically employed.
The head lifting tab slides on the load ramp during loading and unloading, and rests on the load ramp to support the actuator while the heads are in an unloaded state (that is, the heads are positioned off of the disk). During loading, the head lifting tab slides along the load ramp until it reaches the end of the load ramp. Upon reaching the end of the load ramp, the lifting tab slides off of the load ramp and the heads of the actuator engage the storage medium. Similarly, during unloading, the lifting tab slidably engages the end of the load ramp and slides onto the load ramp and thereby lifts the heads away from the disk cartridge.
The lifting tab configuration preferably is lightweight to minimize the mass extending from the suspension, yet have sufficient strength such that deflection of the suspension is within a predetermined amount to prevent damage to the lifting tab, heads, or other components. The trend toward higher a real density, which diminishes the magnetic charge of the information and slider flying height, often has diminishes slider height. For example, disk drives using MR heads are growing in popularity, and are significantly thinner than thin film heads that have often been employed. Thinner heads, such as MR heads, cause a diminished gap (compared with thicker heads) between the suspension arm and the disk surface, which is problematic for the load ramp design and manufacturing.
In configurations in which the load ramp extends over top the disk surface, the diminished gap requires load ramps having even thinner ends. This is especially problematic for removable cartridge drives because the disk must be accurately positioned numerous times, and interchangeable cartridges might not have uniform dimensions because of manufacturing tolerances. Producing load ramps that have uniform, knife-like edges by conventional plastic manufacturing is difficult. Further, the plastic load ramp may wear after repeated loading and unloading cycles. Such wear may cause damage to the disk if the head is not sufficiently lifted. Further, the wear exacerbates the difficulties related to ramp edge thinness.
Dust infiltration into removable media cartridges is another important factor because of the trend toward higher a real density. Further, the cartridge may create particles because moving parts within the cartridge may abrade and form particles that can contaminate the media. Protection of recording media from dust is an important aspect of disk drive design.
It is a goal of the present invention to create a latch system that is easy to manufacture and avoids the drawbacks of the prior art.